Various meter box locking lids used a slot, or in this case a not-so-straight key slot to lock the lid; many today just use the not-so-even five-sided bolt to lock the lids. When all else fails to turn the water off to a house, most jump to the meter; some home's yard watering systems tap the line between the meter and the house, so secure the home does nothing for the yard watering manifold.
Torque pressure in pounds, or newtons, is measured when tightening a nut or bolt; usually enough to keep the nut or bolt from coming undone and stopping before either breaks or sheers. This tool does not measure torque. Most Gas and Water line valves are 90-degree turns; usually the valve's stem is parallel to the line if open, across the line if closed (think of it as a gate), and is usually (if well maintained) as easy to turn as most bathroom door knobs. If you're asking about required tightness of a water, gas or other type of valve (beyond the above) you need to refer to that particular valve's manufacturer. If you're asking what the breaking strength of this tool is, go to the manufacturer's website; hint: if you broke this wrench trying to close a valve, either the valve is broken or already closed.
Contact manufacturer Orbit. It is marketed as a gas valve safety tool though, made of a "non-sparking alloy" and rubber, per Orbit's website.
Ed, that opening is 2.125 inches wide and 0.625 inches tall.
Usually you'll desire a square socket wrench or key for the gas valve, fitting either a 1/4" or 5/16" gas valve stem. Check gas valve areas or residential gas fireplace accessories.
Not sure what a size 8 meter is, but this will work with standard and Texas meter covers.
Go to your local plumbing supply store; most such stores carry supplies used locally. Keys have to fit locks, some locks are odd shaped bolts, some are switch-like under the lid. Or call your utility company to come out.
Yes. The slot for the gas was a little big for my gas meter, but it still works.
Yes, the tool has the appropriate water shutoff valve connector to shut off near the sidewalk. Just make sure that you can reach the valve on the water pipe (in the sidewalk hole) because sometimes an extension is necessary to reach the valve from the top of the hole. Water main service people have such an extension tool but most homeowners do not and this tool may not be long enough.